Canfan s 600 and the speed control

When i use the speed controller and have it on anything less than high...the fan hums at a reasonable volume...louder and more annoying that the fan at full speed...

Did i get a bad unit or is that just normal?

Sent from my SAMSUNG-SM-N900A using Rollitup mobile app

Normal. Theres a PWM type u can get but they run a few hundred dollars...no hum with those. I decided to ditch the fan speed controller and just put on a duct silencer and some duct wrap/insulated ducting. Much more effective.